From time to time, railroad cars derail and must be lifted and placed back upon the rails. The modern technique for rerailing cars is to lift them with a large crane having a lifting cable that terminates in a hook, generally a foundry (or factory) hook. The Association of American Railroads has recommended a provision for lifting a freight car comprising an opening in the horizontal structure such as a horizontal flange of the side sill or an opening in the bottom plate of the body bolster. This provision has the definite disadvantage of weakening the railroad car understructure at the side sill and/or the bolster. Thus, the understructure is weakened at the very location where strength is most needed during the lifting and rerailing of the railroad car. Consider that the same recommendation requires that the provision be designed to withstand a force of 40% of the gross weight applied at 15.degree. of the vertical axis of the upright car. (AAR Standard S-234-78). The load must be supported without exceeding the yield strength of the material comprising the understructure except for very local deformation permitted to achieve bearing area.
Roping staples are longitudinal and vertical openings that serve the function of "cabling" cars. Cabling is a technique for towing railroad cars from a vehicle travelling substantially parallel to the track upon which the railroad car rides. The Association of American Railroads recommends that the roping staple be designed to pull 6 fully-loaded cars equipped with roller bearings on tangent track with a 1% grade (AAR Standards).
Typically, the railroad cars are cabled or pulled by a car puller located adjacent the track upon which the car is loaded. For design purposes, the cable load is considered 22,000 pounds and the cable is considered to be at an angle of 10.degree. horizontally and 10.degree. vertically from the roping staple. The roping staple must withstand the forces applied by the pulling cable and facilitate direct access.
U.S. Pat. Nos. 728,212 and 1,341,787 are directed to roping staples and lifting lugs for securing to the side sill of a railroad car near the side bolster. Each of these patents discloses a device that does not require holes be placed in the side sill and/or bolster except for the fasteners.
The earlier patent merely discloses a roping hook which is not arranged to accommodate a lifting hook except a very large angle be formed between the plane of symmetry of the hook and the vertical cable to which the hook is attached. The latter patent discloses a very complex shape which probably can only be formed by casting. The casting has an opening for receiving a hook which will form a large angle between the plane thereof and the vertical cable. In each case, the lifting hook is supported by the tensile strength of the annular portion of the device surrounding the opening in which a hook may be placed much the same as a chain length supports a tensile load of the chain.
It is an object of this invention to provide a simple, rugged device which can be bolted or welded to the side sill near the bolster to provide a location at which a lifting hook can be inserted and/or cables for cabling can be secured. The load is transferred from the lifting hook to the underframe through the device substantially entirely by compressive forces. Moreover, aside from bolt or rivet holes, there is no need to place holes in the elements comprising the understructure of the railroad car thus preventing an undesirable weaking of the understructure where strength is especially required. The hook of the type currently used for rerailing cars (for example a 504 factory hook) can directly engage the device eliminating any requirements for auxiliary chains and hooks.